Almost all Refillable Cartridges have two holes in them. One is the 'Refill hole' and the other is a 'Air Vent Hole'. The 'Air Vent hole' has either a yellow tape or a plug covering it. This tape or plug has to be removed in order for your printer to be able to draw ink through the cartridge. If the cartridges are low on ink, you can refill the cartridges through the 'refill hole'. Just carefully remove the plug associated with it and put ink though there. We recommend that you remove the cartridges PRIOR to refilling them. If you refill it while it is inside the printer, you can overfill the cartridge and ink will spill inside of it.

The main thing is to find out which hole is which. You can refer back to the original listing where you purchased your item to find a picture where each hole is respectively labeled, such as these following pictures:

One trick to know which is the 'Air Vent hole' is that you'll find a square gap of Air between the plug/tape. If you have any doubts to which hole is which, contact us and we'll be able to help you figure it out.

FOR CARTRIDGES WITH SPONGES: Some cartridges have a sponge on the bottom of the cartridges. Mainly Canon and several other HP models have them. If you refill these cartridges outside of your printer, ink can spill from the bottom of the cartridges because of the sponge. We recommend to watch this video to understand how these type of cartridges work:

HOW TO RESET INK LEVELS: Each printer has an internal page counter with a certain page limit, like 400 pages for example. It correlates with the ink levels. As the number of pages you print or head cleanings you preform increases, the ink levels decreases. Once you pass this 'page limit', your printer will indicate either that your 'cartridges can't be recognized' or 'cartridges are empty'. Then you simply remove the cartridges and install them back in. The 'auto reset chips' will trick the printer to think you installed new cartridges. This in turn will reset your ink levels to full.

However, you can not reset the ink levels to full whenever you want to and can only reset it once it goes all the way down to 0%. Some customers have stated that they can reset the ink levels by simply turning the printer off, wait a few minutes and then turn it back on. Just make sure that you aren't printing with refillable cartridges that are actually EMPTY!